526 Prof. Meyen's Report of the Progress of 



forces : to the first would belong the reception of saps and of 

 gases, the combination of gases with one another, the meta- 

 morphosis of the gases into liquids, the change of fluids into 

 solid substances; to the latter, on the other hand, would be- 

 long the exhaling of gases, liquids, &c. 



A memoir by Girou de Buzareingues* has attracted espe- 

 cial notice; it treats exclusively of the organs of the motion 

 of sap in plants. The results of this work are so at variance 

 with those of all other vegetable physiologists that we may- 

 perhaps expect a full refutation of them ; however, the re- 

 stricted limits of this report do not allow us to give more than 

 a general review of it. It will be very easy for all botanists who 

 have especially occupied themselves for many years with ve- 

 getable anatomy, to convince themselves that the observations 

 reported by Girou de Buzareingues on the organs of the motion 

 of sap do not all agree with nature. The observations it is true 

 were made with an excellent microscope of Amici; but we 

 must not however ascribe the faults which had crept into this 

 work to the instrument, for I, who am also in possession of a 

 similar instrument, see the objects quite otherwise than Girou 

 has described and figured them. The chief blame of the dis- 

 cordant results of these observations might be ascribed to 

 the mode of observation; for it appears that Girou always 

 pressed the objects between plates of glass, and observed them 

 in a pressed condition. We cannot sufficiently warn natu- 

 ralists against the application of such pressure in microsco- 

 pical observations. 



Girou commences his memoir with the expression that the 

 sap in plants ascends from the roots to the leaves, and passes 

 from these again to the roots; that it moves from the axis to 

 the periphery, and from this to the axis ; and that there is a 

 gaseous fluid which accompanies this sap. For the effecting 

 of this motion of the sap the plants employ cells and vessels, 

 and these are intercellular vessels to and off-carrying vessels. 

 The intercellular passages (des conduits inter-utriculaires) are 

 separate vessels, which are said to cause the movement of the 

 fluids and gases in all directions (even an explanatory drawing 

 is given in fig. 16. pi. vii. !). To the adducent vessels belong 

 the simple vessels (des vaisseaux jmis), by which are probably 

 meant the fibrous cells and the tubes of the liber; and, 

 further, the spiral tubes or tracheae : to the red ucent vessels 

 belong, on the other hand, the false spiral tubes. 



The fibre which forms the spiral tube is said to be hollow 



* Mem. sur laDistribut'ion et 1e Mouvement dcs Fluides dans lex riantcs. — 

 Ann. dcs Scienc. Nat. 1836. i. p. 226—248. 



